Assertion :The queen honey bee copulates only once in her life time. Reason: The honey bee queen can lay fertilized as well as unfertilized eggs.

The correct option is B (b)
Assertion is correct as queen honey bee only copulates once in her life time with drone (male honeybee).

Reason is also correct as honeybee can lay both fertilized and unfertilized eggs as well but it is not correct explanation of assertion as after copulation queen honeybee store millions of sperms and they can lay eggs through their life. Hence, option B is correct.